Eleanor Mackinnon was directly descended from the English politician and writer Joseph Addison (1672-1719). Born in Tenterfield, NSW, she and her family moved to Sydney in 1882, and she attended Sydney Girls' High School with Louise Mack and Ethel Turner (qq.v.).
Married to physician R. R. S. Mackinnon in 1896, she studied art with the painter Lister W. Lister and wrote poetry, but her greatest achievements were in charitable and political activities. These included lifelong membership of the Royal Society for the Prevention of Cruelty to Animals, being President of the Women's Liberal (Reform) League, and being on the committee of the Bush Book Club, providing books for women in remote areas. Strongly involved with the Red Cross in NSW and being on its central council from 1914 until her death, she founded the world's first Junior Red Cross Division. She founded and for many years edited the Red Cross Record and the Junior Red Cross Record, and compiled Red Cross knitting and cookery books. During World War I she founded and co-edited the War Workers' Gazette. She was involved with the National Association of New South Wales and later, the United Australia Party.
Mackinnon was awarded an OBE in 1918, and continued with Red Cross and other health initiatives, including the establishment of homes for children suffering from tuberculosis and from polio. In 1925 she was an Australian delegate to the League of Nations. She was awarded King George V's Silver Jubilee Medal in 1935.
